CN112479810A - Micro-interface enhanced reaction system and process for preparing ethylene glycol based on ethylene hydration method - Google Patents

Micro-interface enhanced reaction system and process for preparing ethylene glycol based on ethylene hydration method Download PDF

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Publication number
CN112479810A
CN112479810A CN201910862884.4A CN201910862884A CN112479810A CN 112479810 A CN112479810 A CN 112479810A CN 201910862884 A CN201910862884 A CN 201910862884A CN 112479810 A CN112479810 A CN 112479810A
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ethylene
gas
dilute solution
ethylene glycol
reactor
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张志炳
孟为民
周政
王宝荣
杨高东
罗华勋
张锋
李磊
杨国强
田洪舟
曹宇
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Nanjing Institute of Microinterface Technology Co Ltd
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Nanjing Institute of Microinterface Technology Co Ltd
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Priority to CN201910862884.4A priority Critical patent/CN112479810A/en
Priority to PCT/CN2019/120121 priority patent/WO2021047039A1/en
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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D301/00Preparation of oxiranes
    • C07D301/02Synthesis of the oxirane ring
    • C07D301/03Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
    • C07D301/04Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
    • C07D301/08Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
    • C07D301/10Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/09Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis
    • C07C29/10Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/09Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis
    • C07C29/10Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes
    • C07C29/103Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes of cyclic ethers
    • C07C29/106Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes of cyclic ethers of oxiranes
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C31/00Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
    • C07C31/18Polyhydroxylic acyclic alcohols
    • C07C31/20Dihydroxylic alcohols

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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention relates to a micro-interface enhanced reaction system and a process for preparing ethylene glycol based on an ethylene hydration method, wherein the micro-interface enhanced reaction system comprises the following steps: a reactor, an ethylene oxide generator, a micro-interface generator, and the like. According to the invention, the gas containing ethylene oxide is crushed by the micro-interface generator to form micron-sized bubbles with micron scale, and the micron-sized bubbles are mixed with deionized water to form a gas-liquid mixture, so that the phase interface area of gas and liquid phases is increased, and the effect of strengthening mass transfer within a lower preset operation condition range is achieved; meanwhile, the micron-sized bubbles can be fully mixed with the deionized water to form a gas-liquid mixture, and the gas-liquid mixture can ensure that the deionized water in the system can be fully contacted with the gas containing ethylene oxide by fully mixing the gas phase and the liquid phase, so that the reaction efficiency of the system is effectively improved, and the conversion rate of the ethylene glycol is improved.

Description

Micro-interface enhanced reaction system and process for preparing ethylene glycol based on ethylene hydration method
Technical Field
The invention relates to the technical field of ethylene glycol preparation, in particular to a micro-interface enhanced reaction system and a process for preparing ethylene glycol based on an ethylene hydration method.
Background
Ethylene glycol is an important chemical raw material, is found to react with terephthalic acid to generate dimethyl terephthalate, and can be used as a raw material of polyester fiber and polyester plastic, so that the consumption of the ethylene glycol is greatly increased.
At present, glycol is mainly used for manufacturing polyester fiber, and the dosage of the glycol accounts for more than 40 percent of the total dosage of the glycol; secondly, the main raw material of the antifreezing agent accounts for 35 percent of the total amount; in other aspects, such as a chemical reagent, ethylene glycol is mainly used in a stationary liquid for gas chromatography for analyzing low-boiling oxygen-containing compounds, amine compounds, oxygen and nitrogen heterocyclic compounds, and the like, and in addition to the above-mentioned uses, ethylene glycol is widely used in fuel, paint, adhesives, solvents, lubricants, softeners, thickeners, explosives, and the like, and the production technology of ethylene glycol is continuously improved.
According to the literature, the process of synthesizing ethylene glycol can be roughly classified into the ethylene direct hydration method, the ethylene hydration method, the formaldehyde synthesis method, the ethylene carbonate method, the synthesis gas method, the oxidative coupling method, etc., wherein the ethylene hydration method is also called the ethylene oxide hydration method, which is the main method currently used for producing ethylene glycol, and the principle thereof comprises
First, ethylene is converted to ethylene oxide by vapor phase catalytic oxidation using oxygen in the presence of a silver catalyst. Contacting the gas containing the ethylene oxide with a large amount of water under the reaction condition of 150-;
secondly, the ethylene glycol dilute solution passes through a heat exchanger, is cooled after passing through the heat exchanger, enters an expander, blows out volatile components such as acetaldehyde and crotonaldehyde in the expander, and then flows into a storage tank;
and finally, injecting the ethylene glycol dilute solution in the storage tank into an evaporator through a pump body for concentration, and finally feeding the ethylene glycol dilute solution subjected to multiple times of evaporation into a dehydration tower to remove moisture to prepare pure ethylene glycol.
In the above-mentioned prior processes for producing ethylene glycol, the conversion of ethylene glycol is usually achieved by pressurizing and raising the temperature during the contact of the ethylene oxide-containing gas with water.
Based on the technical principle of preparing ethylene glycol by the ethylene hydration method, the prior ethylene hydration method ethylene glycol preparation system and the prior ethylene hydration method ethylene glycol preparation process have the following problems:
firstly, in the contact process of the gas containing ethylene oxide and water, the gas and the liquid are mixed to generate more large bubbles, and the gas and the liquid cannot be fully mixed due to the more and the larger bubbles, so that the conversion rate of the ethylene glycol is reduced, and the reaction rate of the whole gas-liquid system is reduced.
Secondly, the process of contacting the gas containing ethylene oxide with water needs to be carried out under the conditions of high temperature and high pressure, which wastes energy.
Disclosure of Invention
Therefore, the invention provides a micro-interface enhanced reaction system and a process for preparing ethylene glycol based on an ethylene hydration method, which are used for improving the conversion rate and efficiency of preparing ethylene glycol in the prior art.
In one aspect, the present invention provides a micro-interface enhanced reaction system for preparing ethylene glycol based on an ethylene hydration method, comprising:
the reactor is used for providing a reaction site for the gas containing the ethylene oxide and the deionized water to prepare ethylene glycol dilute solution;
an ethylene oxide generator disposed at one side of the reactor to provide a reaction site for ethylene gas and oxygen to produce ethylene oxide, a heat exchanger disposed between the ethylene oxide generator and the reactor to reduce the temperature of the ethylene oxide-containing gas;
the micro-interface generator is arranged in the reactor, converts the pressure energy of gas and/or the kinetic energy of liquid into the surface energy of bubbles and transmits the surface energy to the gas containing ethylene oxide, so that the gas containing ethylene oxide is crushed into micron-sized bubbles with the diameter of more than or equal to 1 mu m and less than 1mm, the mass transfer area between deionized water and the gas containing ethylene oxide is increased, the thickness of a liquid film is reduced, the mass transfer resistance is reduced, and the deionized water and the micron-sized bubbles containing ethylene oxide are mixed to form a gas-liquid mixture after crushing, so that the mass transfer efficiency and the reaction efficiency between the deionized water and the gas containing ethylene oxide are enhanced within a preset operating condition range;
the impurity removal unit is arranged on one side of the reactor and is used for removing volatile components in the ethylene glycol dilute solution;
and the concentration unit is arranged on one side of the impurity removal unit and is used for concentrating the ethylene glycol dilute solution.
Further, the micro-interface generator is a pneumatic micro-interface generator, and the micro-interface generator is arranged in the reactor and used for crushing the gas containing ethylene oxide to form micron-sized bubbles and outputting the micron-sized bubbles into the reactor after the crushing is finished to be mixed with the deionized water in the reactor to form a gas-liquid mixture.
Furthermore, the upper part of the side wall of the reactor is communicated with a first liquid inlet pipe, and the first liquid inlet pipe is used for conveying deionized water into the reactor.
Further, the intercommunication is provided with ethylene intake pipe and oxygen intake pipe on ethylene oxide generator's the lateral wall, the ethylene intake pipe with the oxygen intake pipe be used for respectively to transmit ethylene gas and oxygen in the ethylene oxide generator, ethylene oxide generator's inside is provided with the silver catalyst, the silver catalyst is used for catalyzing ethylene gas and oxygen.
Further, the impurity removing unit comprises:
a first cooler in communication with the reactor, the first cooler configured to cool the dilute glycol solution;
the expander is communicated with the first cooler and used for removing volatile components in the cooled ethylene glycol dilute solution, a gas outlet is formed in the upper end of the expander and used for discharging the volatile components, and the lower end of the expander is communicated with the reactor and used for transmitting part of the ethylene glycol dilute solution in the expander back to the reactor for repeated reaction;
and the ethylene glycol dilute solution storage tank is communicated with the expander and is used for receiving the ethylene glycol dilute solution in which the volatile components are removed in the expander.
Further, the concentration unit includes:
the evaporator is communicated with the impurity removal unit and used for evaporating and concentrating the ethylene glycol dilute solution, a second liquid inlet pipe is communicated with the middle of the side wall of the evaporator and used for receiving the ethylene glycol dilute solution transmitted by the impurity removal unit and transmitting the ethylene glycol dilute solution into the evaporator, a gas discharge pipe is communicated with the upper end of the evaporator and used for discharging evaporated gas, a liquid discharge pipe is communicated with the lower end of the evaporator and used for discharging the concentrated ethylene glycol dilute solution;
the second cooler is communicated with the evaporator and is used for cooling the evaporation gas discharged from the evaporator into liquid and transmitting the liquid back to the evaporator for re-evaporation;
and the dehydrating tower is communicated with the evaporator and is used for dehydrating the concentrated glycol solution.
Further, the evaporator is a central circulating tube evaporator.
In another aspect, the present invention provides a micro-interface enhanced reaction process for preparing ethylene glycol based on an ethylene hydration method, comprising:
step 1: ethylene gas and oxygen are transmitted into the ethylene oxide generator through the ethylene inlet pipe and the oxygen inlet pipe, and the ethylene gas and the oxygen are catalyzed through the silver catalyst to generate ethylene oxide gas;
step 2: adding deionized water into the reactor through a first liquid inlet pipe, transmitting the cooled gas containing ethylene oxide generated in the step 1 into the micro-interface generator through a pump body, crushing the gas containing ethylene oxide by the micro-interface generator to form micron-scale micron-sized bubbles, outputting the micron-scale bubbles into the reactor after the crushing is finished, mixing the micron-scale bubbles with the deionized water in the reactor to form a gas-liquid mixture, and reacting the ethylene oxide in the gas with the deionized water to generate an ethylene glycol dilute solution;
and step 3: the glycol dilute solution in the step 2 is transmitted to the impurity removal unit through a pump body, in the impurity removal unit, the glycol dilute solution firstly enters the first cooler, the glycol dilute solution is cooled by the first cooler and then continues to enter the expander, the glycol dilute solution is further decompressed and cooled in the expander, so that volatile components in the glycol dilute solution are discharged through the gas outlet, one part of the glycol dilute solution after impurity removal enters the glycol dilute solution storage tank, and the other part of the glycol dilute solution after impurity removal is transmitted back to the reactor through the pump body for repeated reaction;
and 4, step 4: the glycol dilute solution entering the glycol dilute solution storage tank in the step 3 is transmitted to the concentration unit through the pump body, in the concentration unit, the glycol dilute solution firstly enters the evaporator through the second liquid inlet pipe, the evaporation gas is discharged through the gas discharge pipe under the evaporation action of the evaporator, the glycol dilute solution enters the second cooler along the second liquid inlet pipe, the evaporation gas is cooled into liquid under the cooling action of the second cooler, the cooled liquid is transmitted back to the evaporator through the pump body for re-evaporation, and the glycol dilute solution is concentrated after being evaporated by the evaporator;
and 5: and 4, feeding the concentrated ethylene glycol dilute solution in the step 4 into the dehydration tower, performing dehydration treatment to obtain ethylene glycol with high purity, and discharging the ethylene glycol through the dehydration tower.
Further, the temperature in the reactor is 60-90 ℃, and the pressure is 1-1.2atm under normal pressure.
Further, the dehydration tower is a plate tower.
Compared with the prior art, the invention has the beneficial effects that the ethylene oxide-containing gas is crushed to form micron-sized bubbles with micron scale, the micron-sized bubbles have physicochemical properties which are not possessed by conventional bubbles, and the calculation formula of the volume and the surface area of the sphere can know that the total surface area of the bubbles is inversely proportional to the diameter of a single bubble under the condition of unchanged total volume, so that the total surface area of the micron-sized bubbles is huge, the micron-sized bubbles and deionized water are mixed to form a gas-liquid mixture, the contact area of the gas phase and the liquid phase is increased, the effect of strengthening mass transfer within a lower preset operation condition range is achieved, and the conversion rate and the efficiency for preparing the ethylene glycol are effectively improved.
Furthermore, the micro-interface generator is a pneumatic micro-interface generator, is arranged in the reactor and is used for crushing the gas containing ethylene oxide to form micron-sized bubbles, outputting the micron-sized bubbles into the reactor after the crushing is finished and mixing the micron-sized bubbles with the deionized water in the reactor to form a gas-liquid mixture, and effectively improves the conversion rate and efficiency of preparing the ethylene glycol.
Furthermore, a first liquid inlet pipe is communicated with the upper portion of the side wall of the reactor and used for conveying deionized water into the reactor, deionized water is added into the reactor through the first liquid inlet pipe, gas containing ethylene oxide generated in the ethylene oxide generator is conveyed into the micro-interface generator through a pump body, the micro-interface generator breaks the gas containing ethylene oxide to form micron-scale bubbles, the micron-scale bubbles are output into the reactor after the breaking is completed and are mixed with the deionized water in the reactor to form a gas-liquid mixture, and the ethylene oxide in the gas reacts with the deionized water to generate ethylene glycol dilute solution.
Further, the intercommunication is provided with ethylene intake pipe and oxygen intake pipe on ethylene oxide generator's the lateral wall, the ethylene intake pipe with the oxygen intake pipe be used for respectively to transmit ethylene gas and oxygen in the ethylene oxide generator, ethylene oxide generator's inside is provided with the silver catalyst, the silver catalyst is used for catalyzing ethylene gas and oxygen, through the ethylene intake pipe with the oxygen intake pipe to transmit ethylene gas and oxygen in the ethylene oxide generator, ethylene gas and oxygen pass through the silver catalyst is catalyzed, generates ethylene oxide gas.
Further, the impurity removing unit comprises:
a first cooler in communication with the reactor, the first cooler configured to cool the dilute glycol solution;
the expander is communicated with the first cooler and used for removing volatile components in the cooled ethylene glycol dilute solution, a gas outlet is formed in the upper end of the expander and used for discharging the volatile components, and the lower end of the expander is communicated with the reactor and used for transmitting part of the ethylene glycol dilute solution in the expander back to the reactor for repeated reaction;
and the ethylene glycol dilute solution storage tank is communicated with the expander and is used for receiving the ethylene glycol dilute solution in which the volatile components are removed in the expander.
The method comprises the steps that the dilute ethylene glycol solution in the reactor is transmitted to the impurity removal unit through a pump body, in the impurity removal unit, the dilute ethylene glycol solution firstly enters the first cooler, the dilute ethylene glycol solution continues to enter the expander after the dilute ethylene glycol solution is cooled by the first cooler, the dilute ethylene glycol solution is further decompressed and cooled in the expander, volatile components in the dilute ethylene glycol solution are discharged through the gas outlet, one part of the dilute ethylene glycol solution after impurity removal enters the dilute ethylene glycol solution storage tank, the other part of the dilute ethylene glycol solution after impurity removal is transmitted back to the reactor through the pump body to perform repeated reaction, repeated circulation is performed on the dilute ethylene glycol solution to remove impurities, and the impurity removal effect is effectively improved.
Further, the concentration unit includes:
the evaporator is communicated with the impurity removal unit and used for evaporating and concentrating the ethylene glycol dilute solution, a second liquid inlet pipe is communicated with the middle of the side wall of the evaporator and used for receiving the ethylene glycol dilute solution transmitted by the impurity removal unit and transmitting the ethylene glycol dilute solution into the evaporator, a gas discharge pipe is communicated with the upper end of the evaporator and used for discharging evaporated gas, a liquid discharge pipe is communicated with the lower end of the evaporator and used for discharging the concentrated ethylene glycol dilute solution;
the second cooler is communicated with the evaporator and is used for cooling the evaporation gas discharged from the evaporator into liquid and transmitting the liquid back to the evaporator for re-evaporation;
and the dehydrating tower is communicated with the evaporator and is used for dehydrating the concentrated glycol solution.
The glycol dilute solution entering the glycol dilute solution storage tank is transmitted to the concentration unit through the pump body, in the concentration unit, the glycol dilute solution firstly enters the evaporator through the second liquid inlet pipe, the evaporation gas is discharged through the gas discharge pipe under the evaporation action of the evaporator, the evaporation gas enters the second cooler along the second liquid inlet pipe, the evaporation gas is cooled into liquid under the cooling action of the second cooler, the cooled liquid is transmitted back to the evaporator through the pump body for re-evaporation, and the glycol dilute solution is concentrated after being evaporated by the evaporator; the evaporator evaporates the moisture in the ethylene glycol dilute solution for many times, effectively removes the moisture in the ethylene glycol dilute solution, and achieves the effect of fully concentrating the ethylene glycol.
The concentrated ethylene glycol dilute solution enters the dehydrating tower, is dehydrated and converted into ethylene glycol with higher purity, and is discharged through the dehydrating tower
Furthermore, the evaporator is a central circulating pipe evaporator developed from evaporators such as a horizontal heating chamber and a coil heating chamber, and compared with old heaters such as the horizontal heating chamber and the coil heating chamber, the central circulating pipe heater has the advantages of good solution circulation, high heat transfer efficiency, compact structure, reliable operation and the like, and when the central circulating pipe heater is used in the concentration unit, the concentration effect of the ethylene glycol dilute solution is better.
Furthermore, the temperature in the reactor is 60-90 ℃, the pressure is 1-1.2atm at normal pressure, compared with the existing reaction process for preparing the ethylene glycol, the reaction condition is reduced to a greater extent, the ethylene glycol is prepared within a lower preset operation condition range, and the energy is saved.
The dehydration tower is a plate tower, the plate tower is a device for separating vapor-liquid or liquid-liquid systems, and the device comprises a cylindrical tower body and horizontal tower plates at certain intervals, the ethylene glycol solution enters the dehydration tower and sequentially flows through each pedal from top to bottom in the motion process of the ethylene glycol solution in the dehydration tower, and is discharged from the bottom of the dehydration tower, and simultaneously, under the action of high temperature, the moisture in the ethylene glycol solution is evaporated from bottom to top and is discharged from the top of the dehydration tower, so that the aim of preparing high-purity ethylene glycol is fulfilled.
Drawings
FIG. 1 is a schematic structural diagram of a micro-interface enhanced reaction system for preparing ethylene glycol based on an ethylene hydration method according to the present invention.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Fig. 1 is a schematic structural diagram of a micro-interface enhanced reaction system for preparing ethylene glycol based on an ethylene hydration method according to the present invention, including:
a reactor 1 for providing a reaction site for ethylene oxide-containing gas and deionized water to prepare a dilute ethylene glycol solution;
an ethylene oxide generator 2 disposed at one side of the reactor to provide a reaction site for ethylene gas and oxygen to produce ethylene oxide, and a heat exchanger 6 disposed between the ethylene oxide generator and the reactor to reduce the temperature of the ethylene oxide-containing gas;
the micro-interface generator 3 is arranged in the reactor, converts the pressure energy of gas and/or the kinetic energy of liquid into the surface energy of bubbles and transmits the surface energy to the gas containing ethylene oxide, so that the gas containing ethylene oxide is crushed into micron-sized bubbles with the diameter of more than or equal to 1 mu m and less than 1mm, the mass transfer area between deionized water and the gas containing ethylene oxide is increased, the thickness of a liquid film is reduced, the mass transfer resistance is reduced, and the deionized water and the micron-sized bubbles containing ethylene oxide are mixed to form a gas-liquid mixture after crushing, so that the mass transfer efficiency and the reaction efficiency between the deionized water and the gas containing ethylene oxide are enhanced within the range of preset operating conditions;
the impurity removal unit 4 is arranged on one side of the reactor and is used for removing volatile components in the ethylene glycol dilute solution;
and the concentration unit 5 is arranged on one side of the impurity removal unit and is used for concentrating the ethylene glycol dilute solution.
Referring to fig. 1, a first liquid inlet pipe 101 is disposed at the upper portion of the sidewall of the reactor, the first liquid inlet pipe is used for conveying deionized water into the reactor, deionized water is added into the reactor through the first liquid inlet pipe, a pump body is used for conveying a gas containing ethylene oxide generated in the ethylene oxide generator into the micro-interface generator, the micro-interface generator crushes the gas containing ethylene oxide into micron-sized bubbles, the micron-sized bubbles are output into the reactor after the crushing is completed and are mixed with the deionized water in the reactor to form a gas-liquid mixture, and ethylene oxide in the gas reacts with the deionized water to generate an ethylene glycol dilute solution.
Referring to fig. 1, an ethylene inlet pipe 201 and an oxygen inlet pipe 202 are communicated with a side wall of the ethylene oxide generator, the ethylene inlet pipe and the oxygen inlet pipe are respectively used for transmitting ethylene gas and oxygen into the ethylene oxide generator, a silver catalyst 203 is arranged inside the ethylene oxide generator, the silver catalyst is used for catalyzing ethylene gas and oxygen, the ethylene gas and oxygen are transmitted into the ethylene oxide generator through the ethylene inlet pipe and the oxygen inlet pipe, and the ethylene gas and oxygen are catalyzed through the silver catalyst to generate ethylene oxide gas.
With continued reference to FIG. 1, the abatement unit includes:
a first cooler 401, which is communicated with the reactor and is used for cooling the ethylene glycol dilute solution;
the expander 402 is communicated with the first cooler, is used for removing volatile components in the cooled ethylene glycol dilute solution, is provided with a gas outlet at the upper end and is used for discharging the volatile components, and is communicated with the reactor at the lower end and is used for transmitting part of the ethylene glycol dilute solution inside the expander back to the reactor for repeated reaction;
and a glycol dilute solution storage tank 403, which is communicated with the expander and is used for receiving the glycol dilute solution after the volatile components are removed from the expander.
The method comprises the steps that the dilute ethylene glycol solution in the reactor is transmitted to the impurity removal unit through a pump body, in the impurity removal unit, the dilute ethylene glycol solution firstly enters the first cooler, the dilute ethylene glycol solution continues to enter the expander after the dilute ethylene glycol solution is cooled by the first cooler, the dilute ethylene glycol solution is further decompressed and cooled in the expander, volatile components in the dilute ethylene glycol solution are discharged through the gas outlet, one part of the dilute ethylene glycol solution after impurity removal enters the dilute ethylene glycol solution storage tank, the other part of the dilute ethylene glycol solution after impurity removal is transmitted back to the reactor through the pump body to perform repeated reaction, repeated circulation is performed on the dilute ethylene glycol solution to remove impurities, and the impurity removal effect is effectively improved.
With continued reference to fig. 1, the concentration unit includes:
the evaporator 501 is communicated with the impurity removing unit and is used for evaporating and concentrating the dilute glycol solution, a second liquid inlet pipe 5011 is communicated with the middle of the side wall of the evaporator and is used for receiving the dilute glycol solution transmitted by the impurity removing unit and transmitting the dilute glycol solution into the evaporator, a gas discharge pipe 5012 is communicated with the upper end of the evaporator and is used for discharging evaporated gas, and a liquid discharge pipe 5013 is communicated with the lower end of the evaporator and is used for discharging the concentrated dilute glycol solution;
a second cooler 502, which is communicated with the evaporator, and is used for cooling the evaporation gas discharged from the evaporator into liquid and transmitting the liquid back to the evaporator for re-evaporation;
a dehydrating tower 503 communicated with the evaporator, the dehydrating tower being configured to dehydrate the concentrated glycol solution.
The glycol dilute solution entering the glycol dilute solution storage tank is transmitted to the concentration unit through the pump body, in the concentration unit, the glycol dilute solution firstly enters the evaporator through the second liquid inlet pipe, the evaporation gas is discharged through the gas discharge pipe under the evaporation action of the evaporator, the evaporation gas enters the second cooler along the second liquid inlet pipe, the evaporation gas is cooled into liquid under the cooling action of the second cooler, the cooled liquid is transmitted back to the evaporator through the pump body for re-evaporation, and the glycol dilute solution is concentrated after being evaporated by the evaporator; the evaporator evaporates the moisture in the ethylene glycol dilute solution for many times, effectively removes the moisture in the ethylene glycol dilute solution, and achieves the effect of fully concentrating the ethylene glycol.
The concentrated ethylene glycol dilute solution enters the dehydrating tower, is dehydrated and converted into ethylene glycol with higher purity, and is discharged through the dehydrating tower
Referring to fig. 1, the evaporator is a central circulation tube evaporator, which is developed from evaporators such as a horizontal heating chamber and a coil heating chamber, and compared with old heaters such as a horizontal heating chamber and a coil heating chamber, the central circulation tube heater has the advantages of good solution circulation, high heat transfer efficiency, compact structure, reliable operation, and the like, and when used in the concentration unit, the concentration effect of the ethylene glycol dilute solution is better.
Referring to fig. 1, the temperature in the reactor is 60-90 ℃, and the pressure is 1-1.2atm under normal pressure, so that compared with the existing reaction process for preparing ethylene glycol, the reaction conditions are reduced to a greater extent, and ethylene glycol is prepared within a lower preset operating condition range, thereby saving energy.
With reference to fig. 1, the dehydration tower is a plate tower, which is a kind of equipment for vapor-liquid or liquid-liquid system separation, and is composed of a cylindrical tower body and horizontal tower plates at certain intervals, the ethylene glycol solution moves in the dehydration tower, and flows through the pedals from top to bottom in sequence in the dehydration tower, and is discharged from the bottom of the dehydration tower, and simultaneously, under the action of high temperature, the water in the ethylene glycol solution is evaporated from bottom to top and is discharged from the top of the dehydration tower, thereby achieving the purpose of preparing high-purity ethylene glycol.
Referring to fig. 1, the present invention provides a micro-interface enhanced reaction process for preparing ethylene glycol based on ethylene hydration method, comprising:
step 1: ethylene gas and oxygen are transmitted into the ethylene oxide generator through the ethylene inlet pipe and the oxygen inlet pipe, and the ethylene gas and the oxygen are catalyzed through the silver catalyst to generate ethylene oxide gas;
step 2: adding deionized water into the reactor through a first liquid inlet pipe, transmitting the cooled gas containing ethylene oxide generated in the step 1 into the micro-interface generator through a pump body, crushing the gas containing ethylene oxide by the micro-interface generator to form micron-scale micron-sized bubbles, outputting the micron-scale bubbles into the reactor after the crushing is finished, mixing the micron-scale bubbles with the deionized water in the reactor to form a gas-liquid mixture, and reacting the ethylene oxide in the gas with the deionized water to generate an ethylene glycol dilute solution;
and step 3: the glycol dilute solution in the step 2 is transmitted to the impurity removal unit through a pump body, in the impurity removal unit, the glycol dilute solution firstly enters the first cooler, the glycol dilute solution is cooled by the first cooler and then continues to enter the expander, the glycol dilute solution is further decompressed and cooled in the expander, so that volatile components in the glycol dilute solution are discharged through the gas outlet, one part of the glycol dilute solution after impurity removal enters the glycol dilute solution storage tank, and the other part of the glycol dilute solution after impurity removal is transmitted back to the reactor through the pump body for repeated reaction;
and 4, step 4: the glycol dilute solution entering the glycol dilute solution storage tank in the step 3 is transmitted to the concentration unit through the pump body, in the concentration unit, the glycol dilute solution firstly enters the evaporator through the second liquid inlet pipe, the evaporation gas is discharged through the gas discharge pipe under the evaporation action of the evaporator, the glycol dilute solution enters the second cooler along the second liquid inlet pipe, the evaporation gas is cooled into liquid under the cooling action of the second cooler, the cooled liquid is transmitted back to the evaporator through the pump body for re-evaporation, and the glycol dilute solution is concentrated after being evaporated by the evaporator;
and 5: and 4, feeding the concentrated ethylene glycol dilute solution in the step 4 into the dehydration tower, performing dehydration treatment to obtain ethylene glycol with high purity, and discharging the ethylene glycol through the dehydration tower.
Example 1
The ethylene glycol preparation is carried out by using the system and the process, wherein:
the temperature of the reactor is 60 ℃, and the pressure in the reactor is 1 atm;
the feed temperature of ethylene gas and oxygen was 168 ℃;
the gas-liquid ratio in the micro-interface generator is 700: 1.
after the system and the process are used, the conversion rate of the ethylene glycol is 92 percent.
The reaction time was 13 h.
Example 2
The ethylene glycol preparation is carried out by using the system and the process, wherein:
the temperature of the reactor is 70 ℃, and the pressure in the reactor is 1.1 atm;
the feed temperature of ethylene gas and oxygen was 168 ℃;
the gas-liquid ratio in the micro-interface generator is 700: 1.
after the system and the process are used, the conversion rate of the ethylene glycol is 93 percent.
The reaction time was 13 h.
Example 3
The ethylene glycol preparation is carried out by using the system and the process, wherein:
the temperature of the reactor is 80 ℃, and the pressure in the reactor is 1.2 atm;
the feed temperature of ethylene gas and oxygen was 168 ℃;
the gas-liquid ratio in the micro-interface generator is 700: 1.
after the system and the process are used, the conversion rate of the ethylene glycol is 92 percent. The reaction time was 12.5 h.
Example 4
The ethylene glycol preparation is carried out by using the system and the process, wherein:
the temperature of the reactor is 85 ℃, and the pressure in the reactor is 1.1 atm;
the feed temperature of ethylene gas and oxygen was 168 ℃;
the gas-liquid ratio in the micro-interface generator is 700: 1.
after the system and the process are used, the conversion rate of the ethylene glycol is 93 percent. The reaction time was 13 h.
Example 5
The ethylene glycol preparation is carried out by using the system and the process, wherein:
the temperature of the reactor is 90 ℃, and the pressure in the reactor is 1.2 atm;
the feed temperature of ethylene gas and oxygen was 168 ℃;
the gas-liquid ratio in the micro-interface generator is 700: 1.
after the system and the process are used, the conversion rate of the ethylene glycol is 92 percent. The reaction time was 13 h.
Example 6
The ethylene glycol preparation is carried out by using the system and the process, wherein:
the temperature of the reactor is 90 ℃, and the pressure in the reactor is 1 atm;
the feed temperature of ethylene gas and oxygen was 168 ℃;
the gas-liquid ratio in the micro-interface generator is 700: 1.
after the system and the process are used, the conversion rate of the ethylene glycol is 93 percent.
The reaction time was 13 h.
Comparative example
The nitric acid preparation was carried out using the prior art, wherein the process parameters selected for this comparative example were the same as those in example 6.
The ethylene glycol conversion was determined to be 61%.
The reaction time was 34 h.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A micro-interface reinforced reaction system for preparing ethylene glycol based on an ethylene hydration method is characterized by comprising:
the reactor is used for providing a reaction site for the gas containing the ethylene oxide and the deionized water to prepare ethylene glycol dilute solution;
an ethylene oxide generator disposed at one side of the reactor to provide a reaction site for ethylene gas and oxygen to produce ethylene oxide, a heat exchanger disposed between the ethylene oxide generator and the reactor to reduce the temperature of the ethylene oxide-containing gas;
the micro-interface generator is arranged in the reactor, converts the pressure energy of gas and/or the kinetic energy of liquid into the surface energy of bubbles and transmits the surface energy to the gas containing ethylene oxide, so that the gas containing ethylene oxide is crushed into micron-sized bubbles with the diameter of more than or equal to 1 mu m and less than 1mm, the mass transfer area between deionized water and the gas containing ethylene oxide is increased, the thickness of a liquid film is reduced, the mass transfer resistance is reduced, and the deionized water and the micron-sized bubbles containing ethylene oxide are mixed to form a gas-liquid mixture after crushing, so that the mass transfer efficiency and the reaction efficiency between the deionized water and the gas containing ethylene oxide are enhanced within a preset operating condition range;
the impurity removal unit is arranged on one side of the reactor and is used for removing volatile components in the ethylene glycol dilute solution;
and the concentration unit is arranged on one side of the impurity removal unit and is used for concentrating the ethylene glycol dilute solution.
2. The system of claim 1, wherein the micro-interface generator is a pneumatic micro-interface generator, and the micro-interface generator is disposed in the reactor and is configured to crush gas containing ethylene oxide to form micron-sized bubbles and output the micron-sized bubbles into the reactor after the crushing is completed to mix with deionized water in the reactor to form a gas-liquid mixture.
3. The system of claim 1, wherein a first inlet pipe is disposed at an upper portion of a sidewall of the reactor, and the first inlet pipe is used for conveying deionized water into the reactor.
4. The micro-interface strengthening reaction system for preparing ethylene glycol based on the ethylene hydration method as claimed in claim 1, wherein an ethylene inlet pipe and an oxygen inlet pipe are communicated with a side wall of the ethylene oxide generator, the ethylene inlet pipe and the oxygen inlet pipe are respectively used for conveying ethylene gas and oxygen into the ethylene oxide generator, a silver catalyst is arranged in the ethylene oxide generator, and the silver catalyst is used for catalyzing ethylene gas and oxygen.
5. The micro-interface enhanced reaction system for preparing the ethylene glycol based on the ethylene hydration method according to claim 1, wherein the impurity removal unit comprises:
a first cooler in communication with the reactor, the first cooler configured to cool the dilute glycol solution;
the expander is communicated with the first cooler and used for removing volatile components in the cooled ethylene glycol dilute solution, a gas outlet is formed in the upper end of the expander and used for discharging the volatile components, and the lower end of the expander is communicated with the reactor and used for transmitting part of the ethylene glycol dilute solution in the expander back to the reactor for repeated reaction;
and the ethylene glycol dilute solution storage tank is communicated with the expander and is used for receiving the ethylene glycol dilute solution in which the volatile components are removed in the expander.
6. The system of claim 1, wherein the concentration unit comprises:
the evaporator is communicated with the impurity removal unit and used for evaporating and concentrating the ethylene glycol dilute solution, a second liquid inlet pipe is communicated with the middle of the side wall of the evaporator and used for receiving the ethylene glycol dilute solution transmitted by the impurity removal unit and transmitting the ethylene glycol dilute solution into the evaporator, a gas discharge pipe is communicated with the upper end of the evaporator and used for discharging evaporated gas, a liquid discharge pipe is communicated with the lower end of the evaporator and used for discharging the concentrated ethylene glycol dilute solution;
the second cooler is communicated with the evaporator and is used for cooling the evaporation gas discharged from the evaporator into liquid and transmitting the liquid back to the evaporator for re-evaporation;
and the dehydrating tower is communicated with the evaporator and is used for dehydrating the concentrated glycol solution.
7. The system of claim 6, wherein the evaporator is a central circulating tube evaporator.
8. A micro-interface enhanced reaction process for preparing ethylene glycol based on an ethylene hydration method is characterized by comprising the following steps:
step 1: ethylene gas and oxygen are transmitted into the ethylene oxide generator through the ethylene inlet pipe and the oxygen inlet pipe, and the ethylene gas and the oxygen are catalyzed through the silver catalyst to generate ethylene oxide gas;
step 2: adding deionized water into the reactor through a first liquid inlet pipe, transmitting the cooled gas containing ethylene oxide generated in the step 1 into the micro-interface generator through a pump body, crushing the gas containing ethylene oxide by the micro-interface generator to form micron-scale micron-sized bubbles, outputting the micron-scale bubbles into the reactor after the crushing is finished, mixing the micron-scale bubbles with the deionized water in the reactor to form a gas-liquid mixture, and reacting the ethylene oxide in the gas with the deionized water to generate an ethylene glycol dilute solution;
and step 3: the glycol dilute solution in the step 2 is transmitted to the impurity removal unit through a pump body, in the impurity removal unit, the glycol dilute solution firstly enters the first cooler, the glycol dilute solution is cooled by the first cooler and then continues to enter the expander, the glycol dilute solution is further decompressed and cooled in the expander, so that volatile components in the glycol dilute solution are discharged through the gas outlet, one part of the glycol dilute solution after impurity removal enters the glycol dilute solution storage tank, and the other part of the glycol dilute solution after impurity removal is transmitted back to the reactor through the pump body for repeated reaction;
and 4, step 4: the glycol dilute solution entering the glycol dilute solution storage tank in the step 3 is transmitted to the concentration unit through the pump body, in the concentration unit, the glycol dilute solution firstly enters the evaporator through the second liquid inlet pipe, the evaporation gas is discharged through the gas discharge pipe under the evaporation action of the evaporator, the glycol dilute solution enters the second cooler along the second liquid inlet pipe, the evaporation gas is cooled into liquid under the cooling action of the second cooler, the cooled liquid is transmitted back to the evaporator through the pump body for re-evaporation, and the glycol dilute solution is concentrated after being evaporated by the evaporator;
and 5: and 4, feeding the concentrated ethylene glycol dilute solution in the step 4 into the dehydration tower, performing dehydration treatment to obtain ethylene glycol with high purity, and discharging the ethylene glycol through the dehydration tower.
9. The micro-interface enhanced reaction process for preparing ethylene glycol based on ethylene hydration method as claimed in claim 8, wherein the temperature in the reactor is 60-90 ℃ and the pressure is 1-1.2 atm.
10. The micro-interface enhanced reaction process for preparing ethylene glycol based on ethylene hydration method of claim 8, wherein the dehydration tower is a plate tower.
CN201910862884.4A 2019-09-12 2019-09-12 Micro-interface enhanced reaction system and process for preparing ethylene glycol based on ethylene hydration method Pending CN112479810A (en)

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PCT/CN2019/120121 WO2021047039A1 (en) 2019-09-12 2019-11-22 Micro-interface strengthening reaction system for preparing ethylene glycol based on ethylene hydration method and process specification

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Application publication date: 20210312